TOC analyzer (Total Organic Carbon Analyzer) is used to quantitatively determine the content of Total Organic Carbon (TOC) in water or materials. By detecting the generation of carbon dioxide, the total amount of organic carbon can be calculated. It is an important tool for evaluating the degree of organic pollution in water quality, materials, etc.
Core functions and principles
Organic compounds are converted into carbon dioxide using ultraviolet oxidation or combustion oxidation methods, and the total organic carbon content is calculated by detecting the carbon content in the carbon dioxide. The main principles include resistance method, ultraviolet method, conductivity method, etc. Some instruments support gas chromatography to improve detection accuracy.
The TOC analyzer converts organic matter in water samples into carbon dioxide (CO ₂) through oxidation technology, and then uses non dispersive infrared detectors or other detectors to measure the concentration of CO ₂, thereby calculating the TOC value in the water sample. The oxidation methods mainly include:
Combustion oxidation method: Burning water samples at high temperatures (such as 900 ℃) to oxidize organic matter into CO ₂. This method has high oxidation efficiency and is suitable for various water samples, but errors may occur due to the loss of volatile organic compounds.
Peroxysulfate oxidation method: Under high temperature and high pressure conditions, persulfate acts as an oxidant to oxidize organic matter into CO ₂. This method is suitable for the determination of soluble organic carbon (DOC), but high concentrations of Cl ⁻ may interfere with the reaction.
Ultraviolet (UV) oxidation method: Using ultraviolet light (185nm) to irradiate water samples to generate oxidants, which oxidize organic matter to CO ₂. This method is easy to operate, but may not be able to oxidize particulate matter and colloids.
Wet oxidation: Combining persulfate with ultraviolet light or heating to improve oxidation efficiency. This method is suitable for high salt water samples, but the concentration of oxidants needs to be optimized to avoid decomposition.
Operation precautions
Sample pretreatment: Filter and adjust the temperature according to the characteristics of the water sample to eliminate interference factors.
Instrument calibration: Regularly calibrate instruments using standard solutions to ensure the accuracy of measurement results.
Maintenance: Regularly clean the oxidation reactor, gas separation device, and detector to prevent blockage or contamination.
Safe operation: Follow the instrument operating procedures to avoid damage to personnel and equipment caused by high temperature, high pressure, or corrosive substances.